Some evidence of the existence of a further factor necessary for growth of the rat

Abstract

THE experiments describe'd in-this paper were designed to ascertain how far the vitamin A-free diet in use in this laboratory could, when supplemented by cod-liver oil, support normal growth. In the early work of this depart- ment (1927) there had been nothing in the behaviour of the rats used in assaying cod-liver oil to suggest any deficiency in the diet. other than vitamin A, for the addition of this substance in a dose of 0 01 g. daily caused resumption of rapid growth in the test rats for a period of 9 weeks, after which the test was discontinued (Fig. It was several months later that a